Charting the evolution of the ages and metallicities of massive galaxies since z=0.7

Detailed studies of the stellar populations of intermediate-redshift galaxies can shed light onto the processes responsible for the significant evolution of the massive galaxy population since z < 1. We have undertaken such a study by means of deep rest-frame optical spectroscopy with IMACS on Magellan on a sample of similar to 80 galaxies selected from CDFS to have stellar masses >10(10) M-circle dot and redshift 0.65 < z < 0.75. We analyse stellar absorption line strengths and interpret them with a Monte Carlo library of star formation histories to derive constraints on mean stellar ages, metallicities and stellar masses. We present here the first characterization of the stellar mass-metallicity and stellar mass-age relations at z similar to 0.7 and their evolution to the present-day.